The present invention relates to soy protein, phytoestrogens and dietary fibres and compositions thereof suitable for preventing, alleviating and/or treating cardiovascular diseases such as arteriosclerosis, hypercholesterolemia, hyperlipidemia, hypertriglyceridemia, hypertension and related cardiovascular diseases. In particular a composition according to the present invention has improved effects in lowering levels of total serum cholesterol and LDL-cholesterol. A composition according to the present invention is also particularly useful in reducing the accumulation of cholesterol in the arterial wall of subjects at high risk for developing cardiovascular disease or already suffering from a cardiovascular disease such as atherosclerosis. A composition according to the present invention is also useful for lowering serum levels of total cholesterol and/or LDL-cholesterol and/or triglycerides and/or homocystein and/or for increasing serum levels of HDL-cholesterol and/or for improving the HDL/LDL-ratio in subjects at risk for developing cardiovascular diseases and in subjects already suffering from an arteriosclerotic condition such as e.g. atherosclerosis or a related cardiovascular disease. The present invention also relates to the use of these compositions in the manufacture of a medicament for treating a subject suffering from cardiovascular diseases, more particularly arteriosclerosis, hypercholesterolemia, hyperlipidemia, hypertriglyceridemia, hypertension and/or related cardiovascular diseases. The present invention also concerns use of a composition according to the present invention in the prevention and/or treatment of said diseases and disorders and for lowering serum levels of total cholesterol and/or LDL-cholesterol and/or triglycerides and/or serum levels of homocystein in subjects. In addition, the present invention also provides methods for preventing and/or treating and/or prophylactically treating and/or alleviating by therapy said diseases and disorders.
Lipid metabolism involves biosynthesis and degradation of e.g. fatty acids, triglycerides and cholesterol. Ingested triglycerides are hydrolysed in the small intestine and hydrolysis products are absorbed by the intestinal mucosa. Due to the relative insolubility of dietary lipids in water, lipid digestion and absorption is facilitated by the action of detergent substances such as bile acids secreted from the gallbladder. Bile acids are essential for lipid digestion and absorption through the intestinal mucosa.
Triglycerides and cholesterol synthesized in the liver are transported in the bloodstream to peripheral tissues by transport proteins called lipoproteins. Lipoproteins are tiny vesicles coated by apoproteins, phospholipids and free cholesterol and with an interior consisting of the more hydrophobic lipids, cholesteryl esters and triglycerides. Apoproteins and lipoproteins are primarily synthesized in the liver. The lipoproteins are capable of performing an apoprotein mediated binding to a receptor on the surface of a cell into which the entire lipoprotein particle is taken up and further metabolised.
Several different families of lipoproteins have been characterized and are traditionally classified by their density as determined by centrifugation. A standard lipoprotein classification scheme may include in increasing order of density, very low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), low-density lipoprotein (LDL), and high-density lipoprotein (HDL).
VLDL contains approximately 60 to 65 percent triglycerides and 5 to 10 percent cholesterol, lecithin and protein. They are relatively large and function in the transport of triglycerides from the liver to tissue. LDL contains approximately 40 to 50 percent cholesterol and 10 to 15 percent triglycerides, lecithin and protein. They are somewhat smaller than VLDL and also function in the transport of cholesterol from the liver to tissue. HDL contains roughly 75 percent lecithin and protein, while the rest is made up of cholesterol and a small amount of triglycerides. They function in the transport of cholesterol from tissue to the liver and, as such, have the opposite function of LDL. Cholesterol esters cannot readily traverse cellular membranes and are taken up by cells in a receptor-mediated process. Once bound to the LDL-receptor, the LDL-particle is internalised by means of endocytosis, and cholesterol and fatty acids are released and further metabolised.
Ongoing investigations of the LDL-receptor-mediated internalization of cholesterol have generated a better understanding of the relationship between dietary cholesterol, plasma cholesterol levels, and the condition of artherosclerosis. It is believed that the white blood cells that accumulate cholesterol at sites of arterial injury contain a receptor termed a scavenger receptor. Like the LDL-receptor, this scavenger receptor acts by the mechanism of endocytosis and mediates internalization of various extracellular materials. However, the scavenger receptor is indiscriminatory and takes up many different types of extracellular materials including oxidized-LDL-particles containing cholesterol. In contrast to the LDL-receptor, the scavenger receptor is not down-regulated by a high concentration of cholesterol in the cell.
In addition to the above-mentioned lipoproteins, the organism also contains a type of lipoproteins called chylomicrons. Chylomicrons contain 90 to 95 percent triglycerides and only a small amount of cholesterol, lecithin and protein, and they function in the transport of triglycerides from the small intestine to e.g. muscles, liver and heart.
The metabolism of cholesterol in the human organism is closely linked to the synthesis, transport and degradation of triglycerides. Cholesterol is an essential lipid component in all mammalian cells. It is used to regulate the fluidity of cellular membranes and serves as a precursor for certain hormones, vitamin D and bile acids. Cholesterol is synthesized in the liver and is transported with the blood to peripheral tissues by lipoproteins. The liver has a dual function in the metabolism of cholesterol since it is capable of both synthesizing cholesterol and converting surplus cholesterol into bile acids. It is also capable of excreting cholesterol into the bile.
Bile acids have ampholytic characteristics and contain both hydrophobic and hydrophilic surfaces. This ampholytic character facilitates a bile acid mediated emulsification of lipids into micelles. The formation of micelles allows digestive attacks by water-soluble enzymes and facilitates lipid absorption through the mucosal cells of the intestine. Bile acids are secreted from the liver and stored in the gallbladder before being passed through the bile duct and into the intestine. Biosynthesis of bile acids represents a major metabolic fate of cholesterol and accounts for more than half of the approximately 800 mg cholesterol that is normally metabolised per day in a normal adult. Even though bile acids in an amount of 400 mg are synthesized each day, significantly more than this amount is secreted into the intestine. Most of the bile acids that are secreted into the upper small intestine are absorbed in the lower small intestine and are recycled to the liver. The process of enterohepatic circulation may amount to as much as 20 to 30 g of bile acids per day. In contrast, daily elimination of bile acids in the faeces amounts to just 0.5 g or less.
Cholesterol acts on three different levels of regulation of its own synthesis. Firstly, it suppresses endogenous cholesterol synthesis by inhibiting HMG-CoA reductase. Secondly, it activates acyl-CoA:cholesterol acyltransferase (ACAT) which is involved in the synthesis of cholesterol esters from cholesterol and fatty acids bound to acyl-CoA. Thirdly, cholesterol regulates synthesis of the LDL-receptor. Accordingly, a decreased synthesis of LDL-receptors will ensure that a cell in which a sufficient amount of cholesterol is already present does not take up cholesterol. This may explain why excessive dietary cholesterol generates a rapid elevation of cholesterol levels in the blood.
The presence of increased amounts of cholesterol in the blood is known to be positively correlated to arteriosclerosis, a condition commonly attributed to the deposition on the inner lining of an arterial wall of plaque in the form of cholesterol and fats. One commonly occurring arterial condition is that of atherosclerotic cardiovascular disease. The condition may eventually progress through several stages. A normal structure of an artery is characterized by discrete focal numbers of adhering monocytes, some intimal foam cells, and some intimal smooth muscle cells, or intimal cell masses at bifurcations. A fatty streak may occur non-symptomatically and involve a layer of foam cells. As arteriosclerosis progresses, the arterial wall will gradually start to harden due to the deposition of lipid and calcium and proliferation of smooth muscle cells, and the cells may eventually become degenerated. As the wall of an artery thickens, hardens, and lose its elasticity during arteriosclerosis, the blood vessels may develop twists and turns and become narrowed so that the heart must work harder to pump the usual amount of blood through the arteries. The condition may progress into a formation of e.g. fibrous plaque. Fibrous plaque is a slowly reversible condition that may develop further into a complicated lesion.
Cellular degeneration is likely to result in a fracture of the arterial wall which in turn leads to the formation of a deposit of calcium, platelet formation and a gradual development of scar tissue that further contributes to cellular degeneration and a substantially reduced elasticity of the arterial wall. Atherosclerosis characterised by a restricted flow of blood through a coronary artery may lead to the development of coronary heart disease, A complicated lesion of an artery is often symptomatic, hardly reversible and may, in severe cases such as thrombosis, be lethal. A decreased flow of blood through an artery may lead to the formation of blood clots and this may eventually lead to thrombosis. If a blood clot forms in a coronary artery, the interruption of the blood flow may result in the death of part of the heart muscle and cause the extremely painful chest pains associated with a heart attack.
Arteriosclerotic symptoms largely depend on the arteries and tissue affected. When arteriosclerosis occurs in the arteries leading to the brain, the decrease in blood flow and oxygen can cause mental confusion and personality changes. A stroke may occur, if an artery in the brain that has been weakened by a rupture or a blood clot prevents blood from flowing to the brain. This may possibly result in e.g. partial paralysis, loss of speech, and sometimes even death. A decrease in the flow of blood through the coronary arteries results in a shortage of oxygen to the heart muscle and causes chest pains and a painful condition called angina pectoris. Angina pectoris is usually caused by a narrowing or an obstruction of a coronary artery. An attack of angina pectoris may be caused by stress or result from physical activities that require an increased supply of blood to the heart.
Although it is well established that cholesterol, lipids and lipoproteins all contribute to the progression of various arteriosclerotic conditions, little is known about the causes of arteriosclerosis. Hereditary conditions clearly play a role in some cases and several socio-economical and life style related factors such as smoking, hypertension, dietary habits and continual stress also contribute to the development of arteriosclerosis.
There is at present no simple cure or medical treatment for arteriosclerosis and doctors usually advise patients to follow a low fat diet, to stop smoking and to exercise regularly. Patients suffering from hypercholesterolemia may be classified into four risk groups: (i) manifest coronary artery disease, (ii) other forms of atherosclerotic vascular disease, (iii) other risk factors for coronary artery disease in the absence of established atherosclerotic cardiovascular disease, and (iv) isolated hypercholesterolemia in the absence of other risk factors. The recommended treatment regimen for risk group (iv) is to give general advice together with the laboratory results to those patients having a total cholesterol level of 5.0-6.4 mmol/l, without any further follow-up. To patients with cholesterol levels in the range of 6.5-7.9 mmol/l and LDL levels  greater than 5.0, mmol/l or an LDL/HDL ratio  greater than 5.0, only non-pharmacological treatment is offered.
Drug treatment of cardiovascular diseases may include the use of calcium channel blockers to expand the arteries so that blood can flow more freely, and anticoagulants to prevent blood clots from forming in diseased arteries. Some studies indicate that compounds such as acetylsalicylic acid and sulphinpyrazone, which may reduce and/or inhibit clotting by reducing platelet reactivity, may also prevent formation of a thrombus. In advanced cases, surgery to replace diseased blood vessels with grafts of healthy arteries may be necessary.
Also, various lipid-lowering drugs have been advocated, as some studies have shown or indicated that even for otherwise healthy patients suffering from mild or moderate hypercholesterolemia, coronary morbidity and mortality is reduced when they are treated with such lipid-lowering drugs. The most widely used lipid-lowering drugs in recent years have been statins, such as HMG-CoA-reductase-inhibitors, bile acid resins, fibrates, nicotinic acid derivatives and various fish oil concentrates with a high content of xcfx89-3-fatty acids.
An increased serum level of triglycerides is now regarded as a risk factor for the development of a cardiovascular disease. importantly, recent studies have indicated that serum levels of triglycerides currently considered as xe2x80x9cnormalxe2x80x9dxe2x88x92200 mg per deciliter of serum may in fact be too high. It has been proposed that the xe2x80x9cnormalxe2x80x9d limit for triglycerides should be reduced by as much as 50 percent as compared to the limit presently regarded as being the xe2x80x9cnormalxe2x80x9d limit (Yahoo News, May 1, 1998). In a group of patients examined over almost 20 years, a serum triglyceride level of more than 100 mg per deciliter serum actually increased the relative risk of contracting a new cardiovascular event by 50 percent and reduced the chance of surviving that event. It was emphasized that so far no clinical trials have examined whether lowering triglyceride levels affects the incidence of subsequent cardiovascular events, and research into the effect of serum triglyceride levels on cardiovascular events lags far behind research directed to establishing the effect of increased cholesterol serum levels on the subsequent development of cardiovascular diseases.
Adlercreutz (Finnish Medical Society, Ann. Med. 29, 95-120 (1997)) has reviewed the phytoestrogen classes of lignans and isoflavones and has described their influences on a range of cellular activities and metabolic events. Soy intake is reported to prevent oxidation of LDL, but no antioxidant mechanism has yet been established. Although isoflavonoids may prevent the development of atherosclerosis, it is a problem to separate the phytoestrogen effect from the effect of other components in foods. It is emphasized that phytoestrogens, particularly in association with soy intake, seem to have a great potential for preventing cardiovascular diseases, but as the area is really in the early stages of development, an established beneficial effect of soy and isoflavonoids in this respect will have to await further studies. It is further stated that despite an abundant literature at this early stage of dietary phytoestrogen research, much work is needed before any recommendation as to phytoestrogen consumption can be made. However, experimental and epidemiological evidence does support the view that these compounds do not have any negative effects and that they may form a group of substances with a great potential in preventive medicine. It is emphasized that at present, no definite recommendations can be made as to the dietary amounts needed for disease prevention. No reference is made to a composition comprising a combination of soy protein, a high content of a phytoestrogen compound, and dietary fibres.
Anderson (N. Eng. J. Med. 333, 276-282 (1995)) analysed a total of 38 clinical trials and concluded that the consumption of soy protein significantly decreases serum levels of total cholesterol, LDL-cholesterol and triglycerides. It was found that ingestion of diets containing soy protein, as compared with control diets, was accompanied by a significant reduction in serum concentrations of total cholesterol, LDL-cholesterol and triglycerides. However, soy protein intake did not significantly affect serum HDL-cholesterol concentrations. The effect of soy protein intake was dependent upon initial cholesterol concentration. Subjects with normal cholesterol levels had non-significant reductions of 3.3 percent, and also subjects with mild hypercholesterolemia had non-significant reductions of 4.4 percent. Only subjects with moderate and severe hypercholesterolemia had significant decreases in cholesterol levels of 7.4 percent and 19.6 percent, respectively. The pattern of changes in serum LDL-cholesterol concentrations was similar to the pattern for total cholesterol concentrations. Also changes in serum triglyceride concentrations were significantly related to the initial serum triglyceride concentrations. Various types of soy proteins were studied, such as isolated soy protein, textured soy protein, or a combination thereof, and it was found that the type of soy protein did not have any significant effect on the net change in serum cholesterol levels. The study did not consider a simultaneous intake of the various types of soy proteins along with dietary fibres. No reference is made to a composition comprising a combination of soy protein, a high content of a phytoestrogen compound, and dietary fibres.
Bakhit (J. Nutr. 124, 213-222 (1993)) studied mildly hypercholesterolemic men receiving a baseline diet and reported that adding of 25 g of soybean protein to a low-fat, low-cholesterol diet lowers total cholesterol concentrations in men with elevated blood lipids. In subjects having lower blood cholesterol concentrations ( less than 5.7 mmol/l), this level of soybean protein intake did not influence blood lipids, and it was suggested that plasma lipids may even be elevated in some subjects following soybean ingestion. Also, other studies have found that in general, individuals with preexisting hypercholesterolemia respond to soybean protein, whereas individuals with normal cholesterol values do not. Bakhit et al. did not observe an additive effect of concurrent ingestion of soybean protein and soybean fibre. No reference is made to a composition comprising a combination of soy protein, a high content of a phytoestrogen compound, and dietary fibres.
Faggiotto (Atherosclerosis Reviews 21, 187-194 (1990)) states that atherosclerosis is an extremely complex disease involving different pathological processes such as inflammation and degeneration. The onset of atherosclerosis and its progression are very subtle, slow and silent processes, often overlapping with a normal ageing process. It is stressed that despite a tremendous quantity of accumulated information, it is not possible to fully explain why atherosclerosis is so common in Western civilization, how fatty streaks develop in young people, how fatty streaks are converted into fibrous plaques, and what the role is of inflammation in e.g. atherosclerosis. It is stated that even when atherosclerosis becomes symptomatic, the treatment of choice often resorts to surgical procedures, as medical intervention has little or no short-term usefulness, unless patients are subjected to a relatively long-term and aggressive therapy. No reference is made to a composition comprising a combination of soy protein, a high content of a phytoestrogen compound, and dietary fibres.
Gooderham (J. Nutr. 126(8), 2000-2006 (1996)) has suggested that although soy protein supplementation to a typical Western diet may indeed increase plasma concentrations of isoflavones, this may not necessarily be sufficient to counter heart disease risk factors such as high serum levels of cholesterol and triglycerides, and platelet aggregation. Any increase in serum levels of isoflavones following intake of a soy rich diet was found to be quite variable among analysed subjects. This was thought to be due to e.g. the timing of the soy protein consumption or the composition of the gut flora. The metabolism of isoflavones in the gut is variable among individuals and remains to be elucidated. It is noted that the levels of isoflavones present in human plasma are most likely not sufficient to mediate a significant inhibition of platelet aggregation. It is stressed that the isoflavones in human plasma predominantly exist in the inactive glucuronide conjugated form, and only a small amount such as approx. 10 percent exists in the active free and sulphate conjugated forms. A lack of an effect of isoflavones on total cholesterol levels in one study was reported to be in agreement with others which also found that soy had little effect in normocholesterolemic individuals, whereas hypercholesterolemic subjects generally exhibited a decreased total and LDL-cholesterol level relative to normocholesterolemic subjects. It was stressed that only a few studies have reported an HDL-cholesterol raising effect due to the consumption of soy protein and that most studies have shown little or no effect on HDL-cholesterol levels. The reported results indicate a similar lack of effect of soy protein on HDL-cholesterol levels in normocholesterolemic subjects. It is emphasized that only recently have isoflavones been examined separately to determine if these compounds are responsible for the lipid lowering effects associated with intake of soy proteins. the administration of purified isoflavones to animals has shown variable results on blood lipids. One study conducted on hypercholesterolemic humans failed to show an effect of purified isoflavones on blood lipid levels. No reference is made to a composition comprising a combination of soy protein, a high content of a phytoestrogen compound, and dietary fibres.
Hendrich (J. Nutr. 1(9 Suppl.), 1789S-1792S (1994)) has reported that isoflavones may be of great potential benefit to human health maintenance and that isoflavones may be health-protective in amounts potentially available from a human diet containing daily soy foods. The food content of isoflavones is in the range of from 0.1 to 1 mg/g in soy foods. Several factors such as variety of soybean, processing and the addition of other ingredients to the food influence isoflavone contents of foods. It is stated that human intestinal bacteria can destroy ingested isoflavones to a great extent and that this may be why only 15 to 20 percent of isoflavones are reported to be recoverable in intact form from the urine and faeces. It is emphasized that much work remains to, determine the relation between concentration of isoflavones in human urine and plasma and the biological effects of the isoflavones. It is noted that although more health-related animal data need to be obtained, the time is approaching when, long-term human feeding trials of purified isoflavones and foods containing isoflavones to examine health-related outcomes may be warranted. No reference is made to a composition comprising a combination of soy protein, a high content of a phytoestrogen compound, and dietary fibres.
Hunninghake (Am J. Med. 97, 504-508 (1994)) discloses an evaluation of hypocholesterolemic effects of a long-term treatment with a mixture of dietary fibres administered twice a day. 59 subjects with moderate hypercholesterolemia who completed the 15-week placebo-controlled study with the dietary fibre were treated for an additional 36 weeks with 20 g/day of fibre. There were no significant effects on the levels of either triglycerides or HDL. Levels of total cholesterol and LDL-cholesterol and the HDL/LDL-ratio were significantly reduced during treatment. The mean percentage reductions from baseline after 51 weeks of treatment were approximately 5 percent for total cholesterol, 9 percent for LDL-cholesterol, and 11 percent for the LDL/HDL ratio. No reference is made to a composition comprising a combination of soy protein, a high content of a phytoestrogen compound, and dietary fibres.
Knight (Maturitas 22, 167-175 (1995)) provides a synopsis of the literature relating principally to the clinical effects of phytoestrogens on the diseases associated with ageing. A review of literature pertaining to cardiovascular diseases states that the protective effects of phytoestrogens are manifested through lipid changes, a decrease in LDL-cholesterol and an increase in HDL-cholesterol, and vascular effects, concerning both vasomotor tone and vessel wall compliance. The consumption of soy protein is reported to alter lipid levels and dietary soy protein appears to be anti-atherogenic when compared with various animal proteins. It is concluded that isoflavones represent a large and exciting group of compounds with potential benefits to many diseases. It is emphasized that current evidence justifies the conclusion that phytoestrogens may be among the dietary factors affording protective effects against heart disease. However, further clinical studies are required to more clearly elucidate their effects. No reference is made to a composition comprising a combination of soy protein, a high content of a phytoestrogen compound, and dietary fibres.
Knight (Obstet. Gynecol. 87, 897-904 (1996)) has reviewed the sources, metabolism, potencies, and clinical effects of phytoestrogens on humans. The review suggests that phytoestrogens are among the dietary factors affording protection against heart disease in vegetarians. Based on epidemiologic and cell line studies, it is emphasized that intervention studies are now an appropriate consideration to assess the clinical effects of phytoestrogens because of the potentially important health benefits associated with the consumption of foods containing these compounds. It is concluded that clinical applications for phytoestrogens are still in their infancy. No reference is made to a composition comprising a combination of soy protein, a high content of a phytoestrogen compound, and dietary fibres.
Packard (Arterioscler. Thromb. Vasc. Biol. 17, 3542-3556 (1997)) has reviewed the heterogeneity in the apoB containing lipoprotein classes and provides an interpretation of kinetic studies of apoB metabolism in the light of underlying structural and functional variations. The review is based on the fact that lipoprotein classes are composed of a limited number of components with distinct properties. However, the basis for this heterogeneity and the consequences for disease are not thoroughly understood. The LDL-fraction is made up of a small number of subtypes of particles with relatively discrete size and density. Subjects with a preponderance of small-sized LDL have a three-fold increased risk of having a myocardial infarction independent of the total concentration of LDL present. No reference is made to a composition comprising a combination of soy protein, a high content of a phytoestrogen compound, and dietary fibres.
Potter (Am. J. Clin. Nutr. 5, 501-506 (1993)) studied the effects of soy protein consumption with and without soy fibre on plasma lipids in mildly hypercholesterolemic men. It was reported that total and LDL-cholesterol concentrations can be lowered significantly in mildly hypercholesterolemic men, as indicated by a replacement of 50 percent of dietary protein with soy protein. Similar reductions in blood lipids were noted for isolated soy protein, whether it was consumed in conjunction with soy cotyledon fibre or cellulose fibre. Plasma triglyceride concentrations were unaffected by the various dietary treatments described in the article. The study did not reveal any additive cholesterol-lowering effect of concurrent intake of cotyledon soy fibre with isolated soy protein, and it was stated that whether or not there is an added benefit in lowering blood cholesterol concentrations from increased concurrent intake of soy protein and fibre in humans is not known. No reference is made to a composition comprising a combination of soy protein, a high content of a phytoestrogen compound, and dietary fibres.
Reinli (Nutr. Cancer 26, 123-148 (1996)) has reviewed the literature for quantitative data on the levels of known phytoestrogens (daidzein, genistein, coumestrol, formononetin and biochanin A) in food plants. It is reported that the isoflavones daidzein and genistein may exist in four related chemical structures, i.e. an aglycone structure (daidzein and genistein), a 7-O-glucoside structure (daidzin and genistin), a 6xe2x80x2-O-acetylglucoside structure (6xe2x80x2-O-acetyldaidzin and 6xe2x80x2-O-acetylgenistin), and a 6xe2x80x2-O-malonylglucoside structure (6xe2x80x2-O-malonyldaidzin and 6xe2x80x2-O-malonylgenistin). The conjugates (7-O-glucosides, 6xe2x80x2-O-acetylglucosides, and 6xe2x80x2-O-malonylglucosides) are transformed to aglycones, which are sometimes called free isoflavones, through hydrolysis in the intestinal tract by xcex2-glucosidase enzymes of gut bacteria. Acid hydrolysis in the stomach may also contribute to the formation of free isoflavones. It is unclear how readily conjugates undergo intestinal hydrolysis and subsequent absorption. It is stressed that isoflavones are metabolised differently by different animals and humans. No reference is made to a composition comprising a combination of soy protein, a high content of a phytoestrogen compound, and dietary fibres.
Sniderman (Am J. Cardiol. 79, 64-67 (1997)) presents a risk factor hypothesis with an emphasis on the integral role of LDL in atherogenesis. It is stressed that a measurement of LDL-cholesterol is an incomplete estimate of the risk attributable to LDL and that other classic risk factors such as e.g. hypertension, diabetes, and smoking exert their proatherogenic potential largely or exclusively by multiplying the malign influences of LDL on the arterial wall. It is acknowledged that small, dense LDL-particles are one of the most common dyslipoproteinemias associated with coronary artery disease. It is reported that elevated levels of lipoprotein (a) are associated with increased coronary risk, but the basis for this is still not clear. No reference is made to a composition comprising a combination of soy protein, a high content of a phytoestrogen compound, and dietary fibres.
WO 95/10512 relates to a process for producing an aglucone isoflavone enriched vegetable protein whey and discloses in one embodiment a whey having a dry basis genistein content of about 2.6 to about 8.7 mg/gram and a dry basis daidzein content of about 2.5 to about 6.0 mg/gram. No reference is made to a composition comprising a combination of soy protein, a high content of a phytoestrogen compound, and dietary fibres.
WO 95/1b529 relates to a process for producing an aglucone isoflavone enriched protein concentrate and discloses in one embodiment a concentrate having on a dry basis a genistein content of about 1.0 to about 2.0 mg/gram and a daidzein content of about 0.7 to about 1.5 mg/gram. No reference is made to a composition comprising a combination of soy protein, a high content of a phytoestrogen compound, and dietary fibres.
WO 95/10530 relates to a process for producing an aqueous extract comprising protein and glucone isoflavones and discloses in one embodiment a vegetable protein isolate having a dry basis genistein content of about 1.5 to about 3.5 mg/gram and a dry basis daidzein content of about 1.0 to about 3.0 mg/gram. No reference is made to a composition comprising a combination of soy protein, a high content of a phytoestrogen compound, and dietary fibres.
WO 97/31546 discloses data from total replacement programmes (for 6 weeks) in weight reduction studies conducted at Karolinska Hospital in Sweden. It is shown that products comprising isolated soy protein and soybean cotyledon fibres reduce serum triglyceride levels by a maximum of 44 percent and cholesterol levels by a maximum of 27 percent for a patient population with a mean initial cholesterol content of 5.6 mmol/l. A mean value of 6.25 mmol/l was determined for all patients having serum cholesterol levels above 6 mmol/l, and for this group of patients a reduction in serum cholesterol levels of 33 percent was observed. Since the reported data were part of a weight reduction programme, a dietary effect and/or an effect related to a weight loss would have contributed to the observed reductions in cholesterol and/or triglycerides. No reference is made to a composition comprising a combination of soy protein, a high content of a phytoestrogen compound, and dietary fibres.
WO 97/37547 discloses an isoflavone-enriched soy protein product having a protein content greater than 60 percent of total dry matter, a total dietary fibre content of less than 4 percent of total dry matter, a sucrose content greater than 10 percent of total dry matter, a total content of sulphur-containing amino acids greater than 2.2 percent of the total amino acid content, a stachyose content of less than 1.5 percent of total dry matter, and a total isoflavone content greater than 2.5 mg/gram, equivalent to 0.25 percent. The use of soy cotyledon fibres is not anticipated and the claimed invention is for use as an ingredient in the production of an edible product and not in a treatment of arteriosclerosis. Also, the product differs from the composition according to the present invention by comprising total dietary fibre in an amount of less than 4 percent of total dry matter, by containing an unusually low amount of stachyose and a high amount of sulphur-containing amino acids.
U.S. Pat. No. 5,320,949 discloses a process for producing an aglucone isoflavone enriched fibre product from a vegetable protein material in the form of a slurry and discloses in one embodiment an aglucone enriched fibre product directly obtainable from said process and having a genistein content of about 1.0 and 2.0 mg/gram and a daidzein content of about 0.7 to 1.7 mg/gram. No reference is made to a composition comprising a combination of soy protein, a high content of a phytoestrogen compound, and dietary fibres. No reference is made to a composition comprising soy cotyledon fibres and a phytoestrogen compound.
U.S. Pat. No. 5,352,384 discloses an aglucone enriched fibre product having a genistein content of about 1.0 to 2.0 mg/gram and a daidzein content of about 0.7 to 1.7 mg/gram. No reference is made to a composition comprising a combination of soy protein, a high content of a phytoestrogen compound, and dietary fibres.
EP 827 698 A2 and EP 827 698 A3 disclose a process for producing an aglucone isoflavone enriched extract from a vegetable material containing isoflavone conjugates and protein. No reference is made to a composition comprising a combination of soy protein, a high content of a phytoestrogen compound, and dietary fibres.
An abstract presented at the American Heart Association""s 38th Annual Conference on Cardiovascular Disease Epidemiology and Prevention held in March 1998 disclosed a reduction in the levels of total and LDL-cholesterol in a subject following intake of a diet supplemented with 25 grams of soy protein containing 4 mg, 25 mg, 42 mg, and 58 mg of isoflavones, respectively. A xe2x80x9cdose-responsexe2x80x9d effect was reported so that increasing amounts of isoflavones were associated with an increasing reduction of cholesterol. A maximum reduction of serum levels of total and LDL-cholesterol of 4 percent and 7 percent, respectively, was reported for the product containing 58 mg of isoflavone. No reference is made to a composition comprising a combination of soy protein, a high content of a phytoestrogen compound, and dietary fibres.
The present invention provides a nutritional composition having a high, fixed amount of a phytoestrogen compound such as e.g. naturally occurring isoflavones. More particularly the present invention provides a nutritional composition of soybean extractable ingredients having a high, fixed amount of a phytoestrogen compound such as e.g. naturally occurring isoflavones.
More particularly, the present invention relates to a combination comprising a) soy protein, preferably isolated soy protein, b) a high content of a plant hormone in the form of a phytoestrogen compound, preferably naturally occurring isoflavones, and c) dietary fibres, preferably soybean fibres, more preferably soybean fibres manufactured from the cotyledon of soybeans hereinafter referred to as soy cotyledon fibres.
The present invention is useful in treating including prophylactically treating cardiovascular diseases such as hypercholesterolemia, hypertriglyceridemia, hyperlipidemia and other cardiovascular diseases such as e.g. arteriosclerosis. It is one objective of the present invention to significantly reduce levels of total serum cholesterol and LDL-cholesterol and triglycerides in a mildly hypercholesterolemic subject. It is another objective of the present invention to significantly reduce levels of total serum cholesterol and LDL-cholesterol and triglycerides in a subject suffering from hypercholesterolemia and/or hyperlipidemia. It is another objective of the present invention to render the arterial wall more resistant to the accumulation of lipoproteins. It is a further objective of the present invention to provide a composition effective in treating and/or prophylactically treating and/or preventing and/or alleviating an arteriosclerotic condition by reducing the influx of cholesterol and/or triglycerides into the endocelium of the arterial wall. Yet another objective of the present invention is to reduce lipid plaque formation. A composition according to the present invention may be comprised in a micronutrient as defined herein below.
Phytoestrogen compounds are naturally occurring plant hormones showing a structural similarity to 17xcex2-estradiol. Phytoestrogens consist of a number of classes including isoflavones, coumestans, lignans and resorcylic acid lactones. The class of isoflavones consists of among others genistein, daidzein, equol, glycitein, biochanin A, formononetin, and O-desmethylangolesin. The isoflavones genistein and daidzein are found almost uniquely in soybeans. When present in the plant the isoflavones are mainly in a glucoside form, i.e. attached to a sugar molecule. Isoflavones in this glucoside form can be deconjugated to yield isoflavones in a so-called aglycone form, which is the biologically more active form of isoflavones and which is absorbed faster and to a greater extent in the human gut than isoflavones in the glucoside form. In vitro studies have examined the relative estrogenic effect exerted by various phytoestrogens including isoflavones. The resulting potencies as compared to estradiol (having a relative potency of 100), have been reported by Knight (Maturitas 22, 167-175 (1995)) for among others genistein (0.084) and daidzein (0.013).
However, the results also showed that the estrogen receptor complexes formed by estradiol and isoflavones such as genistain and daidzein are functionally equivalent, The comparative dissociation constant of genistein for the estrogen receptor, as determined In competitive binding assays, was found to be from 100 to 10,000 times higher than that of estradiol.
The term xe2x80x9cnaturally occurringxe2x80x9d substance as used in the present specification and the appended claims refers to a substance originally isolated from a natural source, such as an animal or a plant, for example a soy plant, or modified forms of such a substance. The naturally occurring substance for use in a composition according to the present invention may be Included in a composition according to the present invention as part of the natural source or in any type of extract, isolate or the like thereof, or it may have been isolated from a plant source or synthesized biologically, microbiologically, or chemically or by any other means.
Soy proteins are involved in a reduction of cholesterol and triglyceride levels, they are easily digestible, and they represent an efficient sole protein source for maintaining the nitrogen balance. Soy isoflavones in high intakes further enhances this effect, Dietary fibres, such as soybean fibres, especially soy cotyledon fibres have been shown to reduce total serum cholesterol levels, to normalise the gastrointestinal function, and to exert no influence on the absorption of essential minerals.
Accordingly, in one aspect the present invention provides a composition comprising
(a) a soy protein source, selected from isolated soy protein, soy protein concentrate, or soy flour, said soy protein source providing an amount of soy protein, which is at least 45 weight percent of the total protein content of the composition, said total protein content providing at least 15 percent of the total energy content of the composition,
(b) at least one phytoestrogen compound in an amount of more than 0.16 weight percent of the soy protein content of the composition, and
(c) dietary fibres in an amount of more than 6 weight percent of the total weight of the composition on a dry basis.
In a more preferred aspect the present invention provides a composition comprising
(a) isolated soy protein in an amount of at least 50 weight percent of the total protein content of the composition, said total protein content providing at least percent of the total energy content of the composition,
(b) at least one phytoestrogen compound in an amount of more than 0.16 weight percent of the soy protein content of the composition, and
(c) soybean fibres in an amount of more than 6 weight percent of the total weight of the composition on a dry basis.
In a most preferred aspect the present invention provides a composition comprising
(a) isolated soy protein in an amount of at least 50 weight percent of the total protein content of the composition, said total protein content providing at least percent of the total energy content of the composition,
(b) at least one phytoestrogen compound in an amount of more than 0.16 weight percent of the say protein content of the composition, and
(c) soy cotyledon fibres in an amount of more than 6 weight percent of the total weight of the composition on a dry basis.
Phytoestrogen compounds are naturally occurring plant substances, which are either structurally or functionally similar to 17xcex2-estradiol or generate estrogenic effects. Phytoestrogens consist of a number of classes including isoflavones, coumestans, lignans and resorcylic acid lactones. Examples of isoflavones according to the present invention are genistein, daidzein, equal, glycitein, blochanin A, formononetin, and O-desmethylangolesin. The phytoestrogen compounds of a composition according to the present invention are, preferably isoflavones, more preferably genistein, daidzein, glycitein and/or equol, yet more preferably genistein and/or daidzein and even more preferably genistein. Genistein and daidzein are found almost uniquely in soybeans. A preferred composition according to the present invention may accordingly comprise a single isoflavone, such as genistein, daidzein, glycitein or equol, or it may comprise at least one isoflavone selected from the group consisting of at least genistein, daidzein, glycitein and equol.
A composition according to the present invention may be capable of preventing and/or alleviating and/or treating and/or prophylactically treating an arteriosclerotic condition by reducing the accumulation of cholesterol in the arterial wall. This inhibitory effect may be mediated by the binding of naturally occurring isoflavones and/or soy peptides to an estrogen receptor or estrogen-like receptor present in the endocelium of an artery. The soy peptides are preferably provided by partial hydrolysis of soy protein.
Both plasma cholesterol and triglyceride levels are usually increased in individuals treated for a cardiovascular disease, and these increased levels, unless reduced by treatment, are likely to promote atherosclerosis and/or coronary heart disease (CHD). Beta-2-receptors are present on many different types of cells including fat cells and cells of the arterial wall. Beta-2-adrenergic receptors are involved in the regulation of triglyceride synthesis in fat cells and according to one presently preferred hypothesis, binding of soy peptides and/or a phytoestrogen compound such as e.g. a naturally occurring isoflavone to a beta-2-receptor present on a fat cell or in an arterial wall is effective in reducing e.g. the synthesis of triglycerides in fat cells and/or the release of triglycerides into the blood stream and/or reducing the influx of cholesterol and/or triglycerides into the arterial wall. The soy peptides are preferably provided by partial hydrolysis of soy protein.
According to a preferred hypothesis, a composition according to the present invention will reduce and/or eliminate one or more of the risk factors for cardiovascular diseases. Accordingly, a composition according to the present invention may be effective in preventing and/or prophylactically treating and/or alleviating and/or treating conditions such as e.g. hypercholesterolemia, hypertriglyceridemia, hypertension and hyperglycemia. A composition according to the present invention may also be capable of reducing, preventing and/or eliminating fatty streak formation and/or fibrous plaque development and/or effective in mediating a regression of one or both of said arteriosclerotic conditions.
According to a preferred hypothesis, a composition according to the present invention will lead to a decrease in total serum cholesterol levels and/or a decrease in serum LDL-cholesterol levels and/or a decrease in serum triglyceride levels and/or effectively increase the HDL/LDL-cholesterol ratio and/or effectively increase serum levels of high-density lipoproteins (HDL) and/or generate a decrease in serum levels of low-density lipoproteins (LDL). It is desirable to achieve an elevated HDL/LDL-cholesterol ratio since this may result in an increased reverse cholesterol transport and a subsequent excretion.
Also, it is believed that a composition according to the present invention will affect ApoB lipoprotein metabolism including the metabolism of a recently discovered class of ApoB comprising lipoprotein particles called small, dense LDL-particles. The LDL-class of lipoproteins is in fact composed of several components with distinct properties. The basis for this heterogeneity and the consequences for disease are at present not thoroughly understood. An increased level of small, dense LDL-particles is one of the most common dyslipoproteinemias associated with coronary artery disease, and serum levels of ApoB are often disproportionately elevated compared with LDL-cholesterol in dyslipoproteinemic patients.
Heterogeneity within lipoprotein classes may be the result of a differing lipid content, a different apoprotein composition, an altered protein conformation or an as yet unidentified structural variation. Subjects with a preponderance of small, dense LDL have an increased risk of suffering a myocardial infarction independent of the total concentration of serum LDL. Accordingly, a composition according to the present invention may be effective in lowering elevated levels of small, dense LDL.
Hypertriglyceridemia is associated with an increase in the clotting activities of thrombogenic factors such as e.g. factor VII and/or factor X and/or factor XII and an increase in the level of the inhibitor of tissue plasminogen activator, PAI-1. The increased inhibitor concentration results in a decreased level of plasminogen synthesis and thus a decreased level of plasminogen stimulated clot lysis. These changes in clotting activities contribute to a procoagulant state. According to one presently preferred hypothesis the present invention also provides a composition effective in normalising levels of homocystein and/or the clotting activities of at least one thrombogenic factor such as e.g. factor VII and/or factor X and/or factor XII by e.g. decreasing the increased activity thereof. Also, a composition according to the present invention may be effective in promoting a decrease in the level of the inhibitor of tissue plasminogen activator, PAI-1, which in turn leads to an increased plasminogen stimulated clot lysis. A composition according to the present invention may also be effective in reducing an increased platelet aggregatability and/or mediating directly or indirectly a reduction in the increased level of lipoprotein (a) associated with a procoagulant state in an arteriosclerotic condition.
Accordingly, in one embodiment the present invention provides a composition effective in reducing and/or eliminating risk factors for coronary heart disease (CHD) in obese subjects. Consequently, a composition according to the present invention may be capable of preventing and/or alleviating and/or treating and/or prophylactically treating and/or eliminating hypertriglyceridemia and/or hypercholesterolemia and/or hyperglycemia and/or hypertension and/or effective in mediating an increased HDL-LDL-cholesterol ratio.
A composition according to the present invention may also be effective in treating dyslipidemia such as e.g. hypertriglyceridemia and/or hypercholesterolemia in connection with increased VLDL, decreased and altered HDL and small dense LDL, and hypertension, all of which are risk factors for atherosclerosis. Accordingly, in one embodiment, a composition according to the present invention may be capable of effectively decreasing and/or eliminating increased serum levels of VLDL, and/or effectively increasing decreased serum levels of HDL, and/or effectively decreasing serum LDL levels including serum levels of small dense LDL. A composition according to the present invention may be capable of preventing and/or treating and/or prophylactically treating and/or alleviating hypertension.
A composition according to the present invention may also be effective in suppressing any effect that would otherwise generate an increased turnover of arterial smooth muscle cells and/or lead to an increased cholesterol ester accumulation in the arterial wall.
In hypercholesterolemia characterised by increased levels of intracellular cholesterol resulting from e.g. increased delivery of LDL-cholesterol via the LDL-receptor, a composition according to the present invention may be effective in reducing the increased activity of the LDL-receptor. A composition according to the present invention may also be capable of alleviating, eliminating and/or treating any decrease in the HDL receptor-mediated cholesterol efflux. Accordingly, a composition according to the invention may be capable of reducing and/or eliminating any enhanced retention of intracellular cholesterol caused by a decreasing HDL receptor-mediated cholesterol efflux.
Modifications of lipoproteins constitute another risk factor for cardiovascular disease. The modification characterised by protein glycosylation is associated with e.g. arteriosclerosis, and glycosylated lipoproteins such as e.g. LDL, IDL, VLDL and HDL can be expected to be functionally abnormal. Accordingly, the accumulation of glycosylated LDL in the plasma can be perceived to enhance cholesterol ester accumulation. Also, glycosylation of HDL can be expected to impair the ability of HDL binding to the HDL receptor. This impaired binding is likely to reduce the level of intracellular cholesterol efflux. Accordingly, glycosylated HDL may well be another factor potentially contributing to the accumulation of cholesterol in the arterial cell wall. A composition according to the present invention may be effective in preventing, alleviating, treating, reducing and/or eliminating lipoprotein glycosylation in the serum of subjects. In addition, a composition according to the present invention may also be effective in preventing lipoprotein modification caused e.g. by oxidation, chemical modification such as chemical cross-linking, or modifications caused by an alteration in the lipid composition of the lipoprotein, such as any increase or decrease in the content of triglycerides, cholesterol esters, free cholesterol, and apolipoproteins.
Glycosylated lipoproteins have been suggested to be the subject of further processing leading to the formation of hyperglycosylated compounds. Glycosylation and hyperglycosylation of proteins including lipoproteins in both plasma and the arterial wall can also be expected to be a risk factor for cardiovascular disease including arteriosclerosis. Accordingly, a composition according to the present invention may be capable of preventing, treating, reducing, alleviating and/or eliminating the accumulation of hyperglycosylated proteins in both serum and cells of the arterial wall. By doing so, the composition is acting to decrease the amount of LDL becoming xe2x80x9ctrappedxe2x80x9d in the arterial wall due to the high degree of glycosylation of arterial wall proteins. A composition according to the present invention may also be effective in alleviating and/or preventing endothelial cell wall alterations generating an increased LDL xe2x80x9ctrappingxe2x80x9d, and it may be effective in restoring the formation of cells with normal permeability and adhesion parameters.
Lipoprotein glycosylation, hyperglycosylation, oxidation and/or auto-oxidative glycosylation, are risk factors for cardiovascular disease such as arteriosclerosis.
Accordingly, a composition according to the present invention may be effective in eliminating, preventing, alleviating, treating and/or reducing any incidence of lipoprotein glycosylation, hyperglycosylation, oxidation and/or auto-oxidative glycosylation. According to one presently preferred hypothesis, the phytoestrogen compound of a composition according to the present invention is capable of counteracting such incidences. The phytoestrogen compound may also be capable of preventing, reducing and/or eliminating the formation of e.g. free radicals that are likely to be involved in such processes, and a composition according to the present invention may be effective in being, promoting, and/or facilitating the formation of an effective antioxidant defence system for counteracting glycosylation, hyperglycosylation, oxidation and/or auto-oxidative glycosylation of serum proteins and proteins including lipoproteins of the arterial cell wall.
A composition according to the present invention may be effectively acting as an antioxidant in preventing lipoprotein oxidation and/or glycosylation. By the term auto-oxidative glycosylation, or glycoxidation, is understood a reaction leading to an oxidative modification and/or cross-linking of proteins. An increased production of free radicals and lipid peroxidation may also contribute to the formation of auto-oxidative glycosylated lipoproteins and this contribution may also be effectively prevented and/or eliminated by a composition according to the present invention.
According to another presently preferred hypothesis, the binding of a phytoestrogen compound such as e.g. an isoflavone, optionally in combination with soy peptides preferably provided by hydrolysis of soy protein, to a receptor in the arterial wall, such as e.g. the estrogen receptor, or an estrogen-like receptor, is involved in or effective in controlling accumulation of lipoproteins in the arterial wall, possibly by regulating the permeability of said wall and/or the mechanism of lipoprotein transport across cellular membranes. Consequently, the binding of isoflavones such as e.g. genistein and/or daidzein to a receptor in the arterial wall may reduce the flux of lipoproteins into the arterial wall. Receptor binding of isoflavones in the arterial wall is particularly effective in controlling, preventing and/or eliminating fatty streak formation and/or fibrous plaque development and/or effective in mediating a regression of one or both of said arteriosclerotic conditions.
According to a particularly preferred hypothesis, binding of an isoflavones such as e.g. genistein and/or daidzein to a receptor in the arterial wall, preferably an estrogen receptor or an estrogen-like receptor, results in an increased nitric oxide synthesis in the endothelial cells of the arterial wall. Nitric oxide is known to exert anti-arteriosclerotic effects including inhibition of platelet adhesion and aggregation, and inhibition of smooth muscle cell proliferation. Soy peptides obtainable by hydrolysis of soy protein may participate in the binding of isoflavones to an estrogen receptor or an estrogen-like receptor or the soy peptides may themselves bind to said receptor and exert an action leading to an increased nitric oxide synthesis.
In another presently preferred hypothesis, the establishment of an oxidative potential that promotes lipoprotein oxidation and/or lipoprotein auto-oxidative glycosylation occurs concomitantly with, and is very likely caused by, a decrease in cellular antioxidative defence systems. Accordingly, a composition according to the present invention may be effective in acting as an antioxidant. This action reduces and/or eliminates LDL, VLDL, IDL and/or HDL susceptibility to oxidation.
Furthermore, a composition according to the present invention may also be effective in reducing an enhanced susceptibility to endothelial injury and/or for alleviating and/or restoring and/or improving an inefficient endothelial cell repair mechanism leading to endothelial dysfunction. One effect of such an action exerted by a composition according to the present invention is to direct macrophage development away from foam cell formation and to increase the potential of generating arterial smooth muscle cells.
In another presently preferred hypothesis, a composition according to the present invention will promote and/or mediate a reduction in arterial wall thickness and lead to a reduction in the amount of LDL entering the wall. It is believed that an increased thickness of the arterial wall is positively associated with an increased uptake of LDL-particles that are likely to either aggregate or oxidize within the cells of the arterial wall.
Also, a composition according to the present invention may be capable of reducing, eliminating and/or preventing the formation of increased serum levels of lipoprotein. (a) in a subject. Lipoprotein (a) levels may primarily be genetically determined, and no current cardiovascular medications are thought effective in lowering serum levels of lipoprotein (a).